DS2782G-5+T&R Maxim Integrated Products, DS2782G-5+T&R Datasheet - Page 22

• Manufacturer Part Number: DS2782G-5+T&R
• Description: IC FUEL GAUGE STND-ALONE 10-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of DS2782G-5+T&R

• Function: Fuel, Gas Gauge/Monitor
• Battery Type: Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
• Voltage - Supply: 2.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-TDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DS2782
MEMORY
The DS2782 has a 256 byte linear memory space with registers for instrumentation, status, and control, as well as
EEPROM memory blocks to store parameters and user information. Byte addresses designated as “Reserved”
return undefined data when read. Reserved bytes should not be written. Several byte registers are paired into two-
byte registers in order to store 16-bit values. The most significant byte (MSB) of the 16 bit value is located at a
even address and the least significant byte (LSB) is located at the next address (odd) byte. When the MSB of a
two-byte register is read, the MSB and LSB are latched simultaneously and held for the duration of the read data
command to prevent updates to the LSB during the read. This ensures synchronization between the two register
bytes. For consistent results, always read the MSB and the LSB of a two-byte register during the same read data
command sequence.
EEPROM memory consists of the NV EEPROM cells overlaid with volatile shadow RAM. The Read Data and Write
Data commands allow the 2-Wire interface to directly accesses only the shadow RAM. The Copy Data and Recall
Data function commands transfer data between the shadow RAM and the EEPROM cells. In order to modify the
data stored in the EEPROM cells, data must be written to the shadow RAM and then copied to the EEPROM. In
order to verify the data stored in the EEPROM cells, the EEPROM data must be recalled to the shadow RAM and
then read from the shadow RAM. See Figure 23.
USER EEPROM
A 16 byte User EEPROM memory (block 0, addresses 20h - 2Fh) provides NV memory that is uncommitted to
other DS2782 functions. Accessing the User EEPROM block does not affect the operation of the DS2782. User
EEPROM is lockable, and once locked, write access is not allowed. The battery pack or host system manufacturer
can program lot codes, date codes and other manufacturing, warranty, or diagnostic information and then lock it to
safeguard the data. User EEPROM can also store parameters for charging to support different size batteries in a
host device as well as auxiliary model data such as time to full charge estimation parameters.
PARAMETER EEPROM
Model data for the cells, as well as application operating parameters are stored in the Parameter EEPROM
memory (block 1, addresses 60h - 7Fh). The ACR (MSB and LSB) and AS registers are automatically saved to
EEPROM when the RARC result crosses 4% boundaries. This allows the DS2782 to be located outside the
protection FETs. In this manner, if a protection device is triggered, the DS2782 cannot lose more that 4% of charge
or discharge data.
Figure 23. EEPROM Access via Shadow RAM
Copy
EEPROM
Write
Serial
Recall
Shadow RAM
Read
Interface
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